tonight about modern health. 43 million people are taking some kind of aspirin every day to prevent heart attacks and strokes. Bu the leading medical journal, journal says daily aspirin could be linked to a small increase in macular degeneration. A lot of questions tonight. Abc's chief medical editor dr. Richard besser is here. So, exactly how much? Reporter: Well, it was a study out of australia. They looked at 2,400 people for 15 years and found that aspirin doubled your risk of macular degeneration, which causes blindness. The risk is small. 3.5%. If you add that to aspirin causing internal bleeding, you have to make sure you are going to benefit from being on aspirin. Report . All the people who take aspirin, thinking it's for their health, where do you start tonight? What do you ask your doctor? Reporter: If you've had a heart attack or stroke, it can be life saving. You need to be on that drug. If you are high risk, did someone in your family have a heart attack or stroke? Do you have other risk factors like smoking, diabetes. If you have those, your doctor can actually tell you what your risk will be of having a heart attack. The bottom line is, if you are low risk, you don't want to be on a drug that can cause problems. And even the tiny aspirin is still aspirin. Reporter: That's right. It can cause problems. All right, thank you richard besser.

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